It is known to use, for packaging and dispensing a fluid product contained in a receptacle which is pressurized using a gas which is not compatible with the fluid product, a receptacle including two compartments which are separated by a moving partition, a first compartment containing the fluid product and being in communication with a valve for dispensing the product, and a second compartment containing the compressed gas. During dispensing, the moving partition moves and/or deforms. The moving partition may be made up of a deformable membrane; it is preferably made up of a piston. This type of device is intended to isolate the fluid product to be dispensed from the propellant gas and thus delay the deterioration of the fluid product by the propellant gas.
However, the moving wall, more particularly when it is made up of a piston, is not always absolutely leaktight either because the seals between the moving wall and the receptacle are not leaktight, or because the moving wall has a certain permeability to the propellant gas. The lower the viscosity of the fluid product and the higher the pressure of the compressed gas in the second compartment, the poorer the sealing. Consequently, during storage, the compressed gas may leak progressively into the first compartment containing the fluid product and this product may be deteriorated after a certain storage time. This problem arises, for example, in the case where the compressed gas is air and where the fluid product is a hair dye.